Two fridges... how to run(temps) maybe overkill?

[RodderB]

We are planning a cross country(lower 48) then up to Alaska trip this summer. Wonder how many people run multiple fridges/freezers and what temps they run at. We have a Whynter 45L in the jeep and a Dometic 35 in the teardrop. The Jeep has solo batt so thinking to run the fridge around 40-50degreesF and mostly keep produce in it. The dometic we are possibly thinking about running as straight freezer as we like to make smoothies(load up at Costco, frozen berries, etc) but might run fridge temps also. The teardrop has dual deep cells and 100watt solar so pending prolong periods of cloudy weather and heat, think it should be ok as freezer.
Its just myself, my girlfriend and the pup so might be a bit over kill but after doing the upper peninsula of Michigan last fall and having limited options for good healthy food(we eat mostly veggie's and try to keep it to local sustainable sourced meats) we figure it better to stock up when we can and not have to worry about it later.
Anyone else running two fridges/freezers? or am I the only one? My friends say I have a cooler fetish, and my lady thought I was crazy contemplating bringing the yeti45 as well.

 

[john61ct]

That's a lot of space for a small rig but up to you.

Running as a freezer uses 2-5x the AH per day, I'd get more solar, or if driving say 4+ hours every day ensure good charging off alt to both banks.

Have a backup jumpstarter.

Better to consolidate to all one House bank for all House loads, unless they need to be split.

Big fat wires and Anderson plugs needed.

 

[RodderB]

Also am curious, have been reading some use small batt operated fans for better efficiency in the cooler? Found one on amazon for under $20 but wondering its actual worth.
The teardrop is not charged by jeep, have not run the wires, and trying not to continue to add projects b4 the trip. So its batts are only solar charged and have a Norco when shore power is avail.
Picking up a backup jumpstarter is on the list but haven't done to much research. Any recommendations? jeep has optima redtop and is the 2.8L diesel .

 

[highdesertranger]

when I run one of my Engels as a freezer this is what I do. I load it up plug it into 120v and run it full cold overnight. this freezes everything in it rock hard. then I turn it down to 4. the dial goes from 0-6 with 6 being the coldest. this keeps everything frozen solid in 95° weather. now if you don't have 120v the question becomes do you have enough power to run full bore for 10 hours. highdesertranger

 

[tanuki.himself]

when I run one of my Engels as a freezer this is what I do. I load it up plug it into 120v and run it full cold overnight. this freezes everything in it rock hard. then I turn it down to 4. the dial goes from 0-6 with 6 being the coldest. this keeps everything frozen solid in 95° weather. now if you don't have 120v the question becomes do you have enough power to run full bore for 10 hours. highdesertranger

interesting - i'm thinking of running an Engel in the same way for Southern Africa, probably mostly off grid so i know i'll need to put enough solar on the roof to keep it powered, but good to know it does keep stuff frozen. I'm thinking of putting it on runners in a camper with quite close-fitting 30mm foam walls round it for extra insulation. Also wondering if the OPs idea about an extra fan to pull the warm air out through a wall vent would be worthwhile, or if the Engel fan is enough to blow it out of a vent by itself

 

[RodderB]

I was actually referring to a fan for the inside of the cooler, have heard the movement keeps things more uniform and quicker cool down for non cold items placed in. Looking at the whynter I would think a additional fan or some foam on the inside to keep the air flow more direct towards the vent exit might be advantageous tho, seems a lot of wasted space as far air flow goes in directing the heat out. My dometic has the factory prefab cover to add insulation but I am thinking about using a emergency blanket and cutting/taping to the exterior of the Whynter to keep extra heat out. Not sure if it would be more beneficial to add some foam around the exterior or if the blanket would be enough. Foam seems more logical although it takes up more space vs emergency blanket as that just seems like wrapping it in tin foil. Also read on this forum a spare sleeping bag can be used as a cheap alternative for a wrap.

 

[rickc]

I'm about halfway through a home-made slider for a big Dometic CFX75-DWZ. The fridge a bit of an oddity from what I can tell in that the controls, compressor, radiator, fan and electric inputs (and usb output) are all on the same side, so for my slider to work I'm going to have to use a 12V extension cable; I want to see the controls from the back of my truck. I believe that the smaller Dometics have the power inputs on the opposite side from the controls. Anyhow, I digress a little; I have been looking at lots of pictures of other's fridges and have to wonder how some of them breathe. If a fridge is insulated, put on a slider and packed tight into a custom wooden box, the radiator must have difficulty relieving heat and this must have a negative impact on fridge efficiency.

 

[DaveInDenver]

I'm trying to wrap my head around putting a fan inside. I suppose the obvious question would be the goal, is it to have an even temperature inside or to minimize cycling. If you agitate the air that's going to assist any heat transfer, which you may or may not be what you want. Usually the goal is to disturb the air inside the fridge as little as possible, since you want it to settle to the bottom and stay there. If you pack items that need to be coldest at the bottom and warmer stuff on top, then the fridge won't have to run as much to keep that temperature gradient.

 

[Steve_P]

The fans I think you're talking about are said to be helpful in a loosely packed upright gas/electric absorption fridge as used in RVs and probably do help with the terrible recovery time on these fridges. I can't see any benefit in a densely packed chest style 12 volt fridge.

 

[john61ct]

Yes venting the hot areas outside always helps.

A fan inside only sometimes, and not if densely packed which is idwal

 

[RodderB]

So it seems general consensus is that a fan is probably not all that worth it and just like in the house a full fridge runs better than a empty one.

I have also been curious about the heat removal too. The fridge in the jeep will have plenty of air space to move around, crack a window, open the door, etc.. but I am wondering especialy if running as a freezer my Dometic in the teardrop being under the counter and closed in the rear hatch, it has very limited air space. My teardrop is home built but even the professional built ones, I don't think I've noticed any venting, and if some people running them in a mostly closed off box in the vehicle it must not be to much of a issue?

 

[RodderB]

This buggar is the little fan i found on amazon I was referring too.

 

[DaveInDenver]

I don't think you're going to break a fridge running in an enclosed box or having blocked vents. I'd think it would shut down before it overheated itself to the point of damage. But it probably isn't running as well as it could with good airflow. Fundamentally it's about moving warm air away and the more efficiently the fridge can do that the less energy it takes, that's what it boils (so to speak) down to.

My Engel isn't in a box or on a slider, but when I pack the truck I try to leave room around it to breath a little while we drive. I figure with the engine running it can run as much as it needs but I still don't want it running constantly anyway, no reason to wear it out. When we park all that stuff comes out and there's nothing enclosing it.

 

[john61ct]

Lots of mobile living spaces provide venting to the outdoors where the 12V fridge is installed.

More of them should do so, especially in hot climates, and with active fans built in.

If designing a DIY, locating your batts nearby, and having cooking fumes also vented that way would also be efficient, even in cold climates there has to be some venting at all times, may as well get multiple use out of it.

But even if the fan is just helping extract excess heat from the fridge's condenser and electronics, that will help both energy consumption and longevity.

 

[BlueCruiser88]

Two fridges for two people is definite over kill. I would employ the KISS method or buy a large dual zone.